LTspice IV Getting Started GuideLTspice IV Getting Started ... 1.pdf · 5 Getting Started using LTspice…

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<ul><li><p>LTspice IV Getting Started GuideLTspice IV Getting Started Guide</p><p>Copyright 2011 Linear Technology. All rights reserved. </p></li><li><p>2</p><p>Benefits of Using LTspice IVBenefits of Using LTspice IV Stable SPICE circuit simulation with</p><p>Unlimited number of nodes</p><p>Outperforms pay-for options</p><p>Unlimited number of nodesSchematic/symbol editorWaveform viewer</p><p>LTspice is also a great schematic capture</p><p>Library of passive devices Fast simulation of switching mode power supplies (SMPS)</p><p>Steady state detectionSteady state detectionTurn on transientStep response</p><p>Over 1100 macromodels ofLinear Technology products500+ SMPS p p</p><p>Efficiency / power computationsAdvanced analysis and simulation options</p><p> 2011 Linear Technology</p><p>Not covered in this presentation</p></li><li><p>3</p><p>How Do You Get LTspice IVHow Do You Get LTspice IV Go to http://www.linear.com/LTspiceLeft click on Download LTspice IV Register for a new MyLinear account to receive updates if you have not done so already </p><p> 2011 Linear Technology</p></li><li><p>Getting Started</p><p>Copyright 2011 Linear Technology. All rights reserved. </p></li><li><p>5</p><p>Getting Started using LTspice IVGetting Started using LTspice IVUse one of the 100s of demo circuits available on linear.com</p><p>Reviewed by Linear Technologys Factory Applications GroupReviewed by Linear Technology s Factory Applications Group </p><p>Use a pre-drafted test fixture (JIG)Provides a good starting pointProvides a good starting point</p><p>Use the schematic editor to create your own designLTspice contains macromodels for most LTC power devicesp p</p><p> 2011 Linear Technology</p></li><li><p>6</p><p>Demo Circuits on linear comDemo Circuits on linear.comGo to http://www.linear.com Enter root part number in the search te oot pa t u be t e sea cbox (e.g. 3411)Select Simulate Tab on the left side Follo the instr ctions pro idedFollow the instructions provided</p><p>If you do not find a demo circuit of interest, use a pre-drafted test </p><p>Download LTspice</p><p>, pfixture covered next</p><p>Download LTspice</p><p>Download Demo Circuit</p><p>C l li f d i i il bl</p><p> 2011 Linear Technology</p><p>Complete list of demo circuits available at www.linear.com/democircuits</p></li><li><p>7</p><p>Demo CircuitDemo CircuitDesigned and Reviewed by Factory Apps Group</p><p>To run a demo circuit jump to the Run and Probe a Run and Probe a Circuit in LTspiceCircuit in LTspice section</p><p>What if I cannot find a demo circuit?a demo circuit?</p><p>It remains the customer's responsibility to verify proper and reliable operation in the actual application</p><p> 2011 Linear Technology</p><p>Printed circuit board layout may significantly affect circuit performance or reliability</p></li><li><p>8</p><p>Getting Started using LTspice IVGetting Started using LTspice IVUse one of the 100s of demo circuits available on linear.com</p><p>Reviewed by Linear Technologys Factory Applications GroupReviewed by Linear Technology s Factory Applications Group </p><p>Use a pre-drafted test fixture (JIG)Provides a good starting pointProvides a good starting point</p><p>Use the schematic editor to create your own designLTspice contains macromodels for most LTC power devicesp p</p><p> 2011 Linear Technology</p></li><li><p>9</p><p>Pre-Drafted Test Fixture (JIG)Pre Drafted Test Fixture (JIG)Used for testing models during developmentProvides a draft starting pointProvides a draft starting point</p><p>Not reviewed by Linear Technologys factory applications team</p><p>It remains the customer's responsibility to verify proper and reliable operation in the actual application</p><p> 2011 Linear Technology</p><p>Printed circuit board layout may significantly affect circuit performance or reliability</p></li><li><p>10</p><p>Start with a New SchematicNew Schematic</p><p>Start with a New Schematic</p><p>Left click on the New Schematic symbol in the Schematic Editor Toolbar</p><p> 2011 Linear Technology</p></li><li><p>11</p><p>Add a Macromodel &amp; Opening Test FixtureAdd a Macromodel &amp; Opening Test FixtureAdd Component</p><p>Left click on the Component symbol in the Schematic Editor ToolbarE t t t t h f th d lEnter root part to search for the model (e.g. 3411)Left click on Open this macromodels test fixturetest fixture</p><p>To run a test fixture, jump to the Run and Run and Probe a Circuit in LTspiceProbe a Circuit in LTspice section</p><p> 2011 Linear Technology</p><p>pp</p></li><li><p>12</p><p>Getting Started using LTspice IVGetting Started using LTspice IVUse one of the 100s of demo circuits available on linear.com</p><p>Reviewed by Linear Technologys Factory Applications GroupReviewed by Linear Technology s Factory Applications Group </p><p>Use a pre-drafted test fixture (JIG)Provides a good starting pointProvides a good starting point</p><p>Use the schematic editor to create your own designLTspice contains macromodels for most LTC power devicesp p</p><p> 2011 Linear Technology</p></li><li><p>Draft a Design Using the Schematic Editor </p><p>Copyright 2011 Linear Technology. All rights reserved. </p></li><li><p>14</p><p>Start with a New SchematicNew Schematic</p><p>Start with a New Schematic</p><p>Left click on the New Schematic symbol in the Schematic Editor Toolbar</p><p>LTspice is also a great schematic captureschematic capture</p><p> 2011 Linear Technology</p></li><li><p>15</p><p>Add a Linear Technology MacromodelAdd a Linear Technology MacromodelAdd Component</p><p>Left click on the Component symbol in the Schematic Editor ToolbarEnter root part to search for the model (e.g. 3411)Left click on OK </p><p> 2011 Linear Technology</p></li><li><p>16</p><p>Getting the Latest DatasheetGetting the Latest DatasheetUse the macromodels shortcuts to download the Datasheetas a reference for your designy g</p><p>Hold Ctrl key and right click (Ctrl right click) over the LT macromodels symbolLeft click on Go to Linear website for datasheet on the dialogLeft click on Go to Linear website for datasheet on the dialog box that appears</p><p>You can also open the macromodel's test fixture as a draft starting pointYou can also open the macromodel s test fixture as a draft starting point</p><p> 2011 Linear Technology</p></li><li><p>17</p><p>Adding Circuit Elements Pl Di dAdding Circuit Elements RotateMirror</p><p>Place DiodePlace Inductor</p><p>Place CapacitorPlace Resistor</p><p>Left click on the desired component in the Schematic Editor ToolbarLeft click on Rotate or Mirror to adjust orientation</p><p>Alternate you can also use Ctrl R and Ctrl M key shortcutsMove the mouse to the position you want to place it</p><p>To cancel or quit a component type, click the right mouse button</p><p>Move the mouse to the position you want to place itLeft click to place it</p><p> 2011 Linear Technology</p><p>click the right mouse button</p></li><li><p>18</p><p>Adding Sources Loads &amp; Additional Circuit ElementsAdding Sources, Loads &amp; Additional Circuit Elements</p><p>Left click on the Component symbol in the Schematic Editor ToolbarSearch directory structure for desired circuit element (e.g. load and voltage)Left click on OKMove the mouse to the position you want to place itLeft click to place it</p><p> 2011 Linear Technology</p><p>Additional Circuit Elements Like Sources and Loads</p></li><li><p>19</p><p>Highlights of Additional Circuit ElementsHighlights of Additional Circuit ElementsLeft click on the Component symbol in the Schematic Editor Toolbar for a directory of additional circuit elements:</p><p>Arbitrary behavioral sourceVoltage dependent voltageCurrent dependent current</p><p>Lossy transmission lineBipolar transistorVoltage controlled switchCurrent dependent current</p><p>Voltage dependent currentCurrent dependent voltageIndependent current source</p><p>gLossless transmission lineUniform RC-lineIndependent voltage sourceIndependent current source</p><p>JFET transistorMutual inductance</p><p>Independent voltage sourceCurrent controlled switchSubcircuit</p><p>MOSFET transistor MESFET transistormany more</p><p> 2011 Linear Technology</p></li><li><p>20</p><p>Drawing Lines and Labeling NodesDrawing Lines and Labeling Nodes</p><p>Draw WirePlace Ground Do not forget to place a </p><p>Lines</p><p>Place GroundLabel Node</p><p>g pground in your design, it is </p><p>required for simulation!</p><p>Left click on the Draw Wire in the Schematic Editor ToolbarLeft click a blue box (terminal)Define the lines path with a left click over intermediate pointsp pLeft click on another blue box (terminal)</p><p> 2011 Linear Technology</p></li><li><p>21</p><p>Editing Circuit Elements DeleteEditing Circuit ElementsDuplicate</p><p>MoveDragagUndo</p><p>Redo</p><p>Left click on the desired editing option</p><p>To organize your layout use the Drag option to move circuit</p><p>g pLeft click on the circuit element</p><p>To organize your layout, use the Drag option to move circuit elements around and to adjust lines between terminals</p><p> 2011 Linear Technology</p></li><li><p>22</p><p>Editing Circuit Elements AttributesEditing Circuit Elements AttributesRight click on the component symbol to modify attributes </p><p>Right click on the text next to the component to edit the Right click on the text next to the component to edit the visible attribute and label </p><p>Pointer will turn into a text caret</p><p> 2011 Linear Technology</p></li><li><p>23</p><p>Use Labels to Specify Units in Circuit Elements AttributesUse Labels to Specify Units in Circuit Elements Attributes</p><p>K = k = kilo = 103</p><p>MEG = meg = 106m = M = milli = 10-3</p><p>u = U = micro = 10-6gG = g = giga = 109</p><p>T = t = terra = 1012n = N = nano = 10-9</p><p>p = P = pico = 10-12</p><p>f = F = femto = 10-15f = F = femto = 10 15</p><p>ImportantImportantUse MEG to specify 106, not MEnter 1 for 1 Farad, not 1F</p><p> 2011 Linear Technology</p></li><li><p>24</p><p>Circuit Elements DatabaseCircuit Elements DatabaseSome components have an available database of manufacturers attributes</p><p>Resistors, capacitors, inductors, diodes, Bipolar transistors, MOSFET transistors, JFET transistorsIndependent voltage and current sources</p><p>To configure a component to a manufactures attributes</p><p>Right click on the component symbolLeft click on Select or Pick NewLeft click on a selected deviceLeft click on a selected deviceLeft click on OK </p><p> 2011 Linear Technology</p></li><li><p>25</p><p>Editing Voltage Sources and LoadsEditing Voltage Sources and LoadsVoltage Source</p><p>Right click the voltage g gsymbolEnter DC voltage value and (optional) Series Resistance Left click on OK</p><p>Load (current)Right click on the loadRight click on the load symbolEnter DC current valueLeft click on OKLeft click on OK</p><p> 2011 Linear Technology</p></li><li><p>26</p><p>Summary of Schematic Editor ToolbarSummary of Schematic Editor ToolbarPlace Circuit Element</p><p>Place DiodePlace InductorPlace Inductor</p><p>Place CapacitorPlace Resistor</p><p>Label NodePlace Ground</p><p>Draw Wire</p><p>MoveDragDragUndo</p><p>RedoRotate</p><p>Mirror</p><p>DeleteDuplicate</p><p> 2011 Linear Technology</p><p>MirrorPlace Comment</p><p>Place SPICE directive</p><p>pPaste b/t Schematics</p><p>Find</p></li><li><p>Run and Probe a Circuit</p><p>Copyright 2011 Linear Technology. All rights reserved. </p></li><li><p>28</p><p>Simulation CommandsSimulation CommandsTo run a simulation, specify the type of analysis to be performedpThere are six different types of analyses: </p><p>Transient analysisSmall signal ACDC sweepNoise</p><p>More information on simulation and dot commands are available in </p><p>LTspice IV User GuideNoiseDC transfer functionDC operating point</p><p>Simulation commands are placed on the schematic as textCalled dot commands</p><p> 2011 Linear Technology</p></li><li><p>29</p><p>Editing Simulation CommandsEditing Simulation CommandsLeft click on Simulation menuLeft click on Edit Simulation Cmd</p><p>Demo Circuits and Test Fixtureshave predefined Simulations </p><p>C dLeft click on Edit Simulation CmdAs a starting point in a simulation</p><p>Left click on Transient tab</p><p>Commands</p><p>Enter a Stop TimeYou may need to adjust this again lateragain later</p><p>Select OK</p><p> 2011 Linear Technology</p></li><li><p>30</p><p>Running a CircuitRunning a CircuitRun</p><p>If model is not found please Sync Release </p><p> 2011 Linear Technology</p><p>p yunder Help menu to update LTspice</p></li><li><p>31</p><p>Probing a Circuit &amp; Waveform ViewerProbing a Circuit &amp; Waveform Viewer Left click on any wire to plot the voltage on the waveform viewer</p><p>Voltage probe cursor</p><p>Left click on the body of the component to plot the current on the waveform</p><p>g p</p><p>to plot the current on the waveform viewer </p><p>Convention of positive current is in pthe direction into the pin </p><p> 2011 Linear Technology</p><p>Current probe cursor</p></li><li><p>32</p><p>Probing a Demo Circuit and Test FixtureProbing a Demo Circuit and Test FixtureDemo Circuits and Test Fixtures have INs and OUTs clearly labeled to help you quickly select themp y q yTo view the waveform left click on IN and OUT</p><p>L ft Cli kLeft Click Left Click Here for Output </p><p>Waveform</p><p>Left Click Here for </p><p>Input Waveform WaveformWaveform</p><p> 2011 Linear Technology</p></li><li><p>33</p><p>Voltage Differences Across NodesVoltage Differences Across NodesLeft click and hold on one node and drag the mouse gto another node</p><p>Red voltage probe at the first nodenodeBlack probe on the second</p><p>Differential voltages are displayed in the waveform </p><p>viewerviewer </p><p> 2011 Linear Technology</p></li><li><p>34</p><p>Plot PlanesPlot PlanesMultiple plot panes can be displayed on one window to allow better separation between traces permitting different traces to be i d d tl t l dindependently autoscaled</p><p>Right click in the waveform paneSelect Add Plot PaneLeft click and hold to drag a label to a new plot pane</p><p> 2011 Linear Technology</p></li><li><p>35</p><p>Zooming In and Out in the Waveform ViewerZooming In and Out in the Waveform ViewerTo zoom in</p><p>Left click and hold as youLeft click and hold as you drag a box about the region you wish to zoom in then releaserelease</p><p>To zoom outRight click and select Zoom to Fit or Zoom Back</p><p>Zoom InPan</p><p> 2011 Linear Technology</p><p>PanZoom Out</p><p>Autoscale</p></li><li><p>36</p><p>Measuring VRi l IRi l and Time (Frequency)Measuring VRipple, IRipple and Time (Frequency)Drag a box about the region you wish to measure (peak to peak over a period)</p><p>Left click and hold to drag a box over the portion of interestView the lower left hand side of the screen </p><p>To avoid resizing shrink your box before you let go of the left mouseTo avoid resizing, shrink your box before you let go of the left mouse click or use the Undo command in the Edit menu</p><p>T i SMPS lt i l illTo view SMPS voltage ripple you will need to zoom into a narrow section </p><p>since waveform is initially compressed to full rangeco p essed to u a ge</p><p> 2011 Linear Technology</p></li><li><p>37</p><p>Average/RMS Current or Voltage CalculationsAverage/RMS Current or Voltage Calculations Hold down Ctrl and left click on the I or V trace label in the waveform viewer</p><p> 2011 Linear Technology</p></li><li><p>38</p><p>Instantaneous &amp; Average Power DissipationInstantaneous &amp; Average Power DissipationInstantaneous Power Dissipation </p><p>Hold down the ALT key and yleft click on the symbol of the componentPointer will change to a thermometer Plotted in units of Watts</p><p>Average Power Dissipation Hold down the Ctrl key and left click on the trace labelleft click on the trace labelpower dissipation waveform </p><p> 2011 Linear Technology</p></li><li><p>Generating a BOM and Efficiency Report</p><p>Copyright 2011 Linear Technology. All rights reserved. </p></li><li><p>40</p><p>Bill of Materials (BOM)Bill of Materials (BOM)Left click on View menuLeft click on Bill of MaterialsLeft click on Bill of Materials</p><p> 2011 Linear Technology</p></li><li><p>41</p><p>Computing Efficiency of SMPS CircuitsComputing Efficiency of SMPS CircuitsLeft click on Simulate menuLeft click on Edit Simulation CmdLeft click on Edit Simulation CmdLeft click on Stop simulating if steady state is detected</p><p>Automatically detect the steady state by checking the internal y y y gstate of the macromodels</p><p>Rerun simulation Automatic detection of steady state may not work steady state detection may be too strict or lenient</p><p> 2011 Linear Technology</p></li><li><p>42</p><p>Viewing Efficiency ReportViewing Efficiency ReportLeft click on Simulate menuLeft click on Efficiency ReportLeft click on Efficiency Report</p><p> 2011 Linear Technology</p></li><li><p>Simulate a Transient Response in a SMPSAdvanced Topic</p><p>Copyright 2011 Linear Technology. All rights reserved. </p></li><li><p>44</p><p>Us...</p></li></ul>

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